The last time I had been to the Cambridge Corn Exchange it was to see Richard Thompson, so the American evangelical Rob Bell made an interesting contrast last week. Both men pulled in about the same size of comfortably bohemian crowd; a few pony tails and a general air of beer and niceness. Bell's crowd was a little younger and than Thompson's.

In America, he's a huge star. He's probably the most prominent of the upcoming generation of evangelical megachurch leaders, who will follow Rick Warren's. He's been on the cover of Time magazine and he's been denounced all over YouTube for his supposed liberalism.

Last week he had a dedicated heckler outside the entrance to the Corn Exchange: a young man in a black suit and tie, with a clean white shirt who held a black-bound Bible up while he shouted about the gospel. This wasn't because he wanted Fairport Convention reformed: Bell's apostasy is to doubt that everyone is in hell who does not share his theology.

Some of Bell's audience leant over the rails at the front of the Corn Exchange and heckled the heckler back. In a Thompson-esque touch, one kind woman even gave me a roll-up while she shouted "fundie" at him. This little smoulder was the closest that we came to the fires of hell.

On stage with our own Maggi Dawn, Bell was a fascinating performer. What he said made very little impression on me compared to the conviction and elegance with which he said it. He was always in movement or absolutely at rest; he never fidgeted or slumped. In this he reminded me of Tony Blair, but where Blair, the last time I saw him preach at his Foundation, used a lectern, Bell performed on a largely bare stage and was altogether more active, as if he were dancing out a three-card trick with his feet while he expounded his theology. Sometimes he spread his arms like an aeroplane's wings. I half expected him to take off while he zoomed around the stage.

The audience loved him, and he treated them skill and kindness. He spoke entirely without notes, and with tremendous fluency and a knack of seeming to talk to us all as individuals. He spoke well of his wife, and told a story of a miraculous return from the dead in Los Angeles. When he was asked a tricky question, he would say "That's a very good question; thank you" before evading it. He would not even say that Judas was in hell. That may be entirely orthodox, but it is also rather brave.

After the talk, when an old-fashioned evangelical meeting would have had an altar call, Bell summoned the congregation up to get their copies of his books signed.

This is one future for evangelical Christianity, and not a bad one. He has been attacked for being a fundamentalist in quasi-Anglican clothing, and for being a quasi-Anglican pretending to be a fundamentalist. But I don't think his theology matters very much, whatever it may be. If it fits into Greenbelt comfortably, that's a certificate of wholesomeness.

What I think is really distinctive about him is that he is an entirely post-televisual preacher. Close up he is much bigger than he looks on stage: tall, broad-shouldered: his face is proportionately large, so that his eyes seem startlingly far apart when he looks down at you. But whereas an old-fashioned preacher, like Dan Dennett or Ian Paisley, is very content to be physically imposing, Bell seems to want to fit into the corner of any living room, intimate and unthreatening as a familiar face on television. It's almost as if the American evangelical movement had re-invented the vicar.